How would I build a footstep pressure sensor?
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I'm thinking of making a costume with some electronics in it. I'd like to have a speaker that plays a stomp sound when I take a step. For that, of course, I'd need some sort of way to detect that I'm taking a step.
The obvious answer is to put some sort of switch in the footwear that will close a circuit and send a signal when my foot presses down on it, but that presents some problems of its own. First, I don't want something bulky that feels like I'm stepping on something or like I have a rock in my shoe or... etc. You get the point. Second, if I'm going to be standing on it, whatever it is needs to be able to bear the weight of my body (in the 150-170 lbs range) without any risk of breaking.
Any DIYers out there have any ideas as to how to do something like this?
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@masonwheeler said in How would I build a footstep pressure sensor?:
Any DIYers out there have any ideas as to how to do something like this?
Not much of a DIYer, but the most basic idea would probably be just a pushbutton protruding slightly from the sole of the shoe - but that seems like it'd need careful tuning so that it triggers neither too easily (since you want to avoid the circuit closing when you shift your weight slightly from one leg to the other), or too hardly (since you probably don't want to have to slam your foot down to trigger it).
Or just hide the switch near your big toe and learn to flick/tap it in rhythm with your steps?
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Something like this might help?
Fast Vibration Sensor Switch (Easy to trigger)
The "poor man's" accelerometer/motion sensor! These spring-vibration switches are high sensitivity non-directional vibration induced trigger switches. Inside is a very soft ...
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Craft two stone blocks together into a pressure plate.
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@pie_flavor said in How would I build a footstep pressure sensor?:
Craft two stone blocks together into a pressure plate.
Or wood planks
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@sloosecannon said in How would I build a footstep pressure sensor?:
@pie_flavor said in How would I build a footstep pressure sensor?:
Craft two stone blocks together into a pressure plate.
Or wood planks
Nah, remember you don't want it being light enough that shifting your weight would fuck it up
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Something like this pressure sensor? It's for up to 100lbs according to the sparkfun page, but the datasheet states that you can use it up to 1000lbs with a small change to measuring circuit.
Either way, there's no mechanical components in the sensor, so it should be harder to break, even if you max out the pressure.
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Two sheets of foil with carefully placed foam in between. Wont last forever though.
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@cvi said in How would I build a footstep pressure sensor?:
Something like this pressure sensor? It's for up to 100lbs according to the sparkfun page, but the datasheet states that you can use it up to 1000lbs with a small change to measuring circuit.
Either way, there's no mechanical components in the sensor, so it should be harder to break, even if you max out the pressure.
I second that - a piezo is the way to go.
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Open up a simple (not overly digital) step counter and solder some wires to it?
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@ben_warre said in How would I build a footstep pressure sensor?:
Two sheets of foil with carefully placed foam in between. Wont last forever though.
You can make a fairly robust one from the conductive foam that semiconductors are usually shipped in. I made an "alarm mat" to put in front of my room with it as a teen.
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Put something conductive on the bottom of the shoes, and something else conductive on the bottom of your foot-- the arch part which is "floating" until you take your step. Or behind the toes possibly. Experiment a bit.
When you step the circuit is completed.
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This might lead you down the right path:
Or perhaps a strain gauge? Though those can be pretty pricey for a novelty one-off.
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@pie_flavor said in How would I build a footstep pressure sensor?:
Craft two stone blocks together into a pressure plate.
God damn it. I saw the topic title and was so excited to be able to make that joke.
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@polygeekery said in How would I build a footstep pressure sensor?:
This might lead you down the right path:
Or perhaps a strain gauge? Though those can be pretty pricey for a novelty one-off.
I dunno, all these household hacks ideas almost seem more expensive and finicky when put against my $1 (I guess that doesn't include shipping) guaranteed solution.
If you want to pair it with one of these all you'd need is a long cable:
https://www.amazon.com/Funnytoday365-10Secs-Recordable-Module-Buttons/dp/B01LJQXNDY/
https://www.amazon.com/Recording-Playback-Module-Loudspeaker-Generic/dp/B010ND0KDK/
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@tsaukpaetra Your solution is a non-directional motion sensor; that would give all sorts of false positives. I'm looking for a directional pressure sensor.
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@masonwheeler said in How would I build a footstep pressure sensor?:
@tsaukpaetra Your solution is a non-directional motion sensor; that would give all sorts of false positives. I'm looking for a directional pressure sensor.
Seems to work fine on kids' shoes.
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You could also try to use a photo cell/diode, if you can mount it beneath the shoes. Essentially, when you put the foot down, all light to it will be blocked; if you lift the foot, there will be some ambient light entering the photo sensor. Add a weak LED next to it if you plan to use this in a really dark environment; I guess you can use IR if you go the LED route, so it won't be visible. You should be able to get these quite easily, and the cost would be not much more than $1.
That might be cheap/easy enough to just try out. After that, I'd probably go for a force sensor, mostly because that seems fairly reliable and easy to set up. Adafruit has some for $7...
